1. Field of Invention
The present invention relates to an alternate radio transmitter and a method for operating the same and, more particularly, to a radio transmitter for transmitting data including global positioning system (“GPS”) data.
2. Related Prior Art
After a sea wreck or airplane crash, searching is conducted for survivors, bodies, and wrecks of a ship or airplane. The area wherein the searching is to be conducted is determined in two manners. The area is determined to be the spot where the ship or airplane is detected by radar the last time. Alternatively, the area is determined to be the spot where a SOS signal is sent from the ship or airplane the last time. A rescue team is sent to the area. However, there are only about 72 hours for any survivors to be saved. After that, the chance for the survivors to be rescued is slim. The chance would be even lower if there is hypothermia due to bad weather or freezing cold sea water. Hence, it is important to know where to conduct such searing soon. It is however difficult to use radar to detect the wrecks, particularly those of the airplane which are often scattered.
A personal location beacon (“PLB”) is helpful for a rescue team to locate a survivor or body in a sea wreck or airplane crash. The PLB includes a 121.5 MHz module and a 406 MHz module and therefore operates based on two frequencies: 121.5 MHz and 406 MHz, and transmits signals via a satellite. Hence, the PLB includes a complicated circuit. The 121.5 MHz module includes a direction finder to search for sound-guided signals. In a phase modulation (“PM”) manner, the 406 MHz module transmits GPS signals to and saves the GPS data in a GEOSAR. The GEOSAR transfers the GPS data to a local user terminal (“LUT”). However, the GEOSAR sends the GPS data to an LUT only when it reaches one. It might take a lot of precious time for the GEOSAR to reach an LUT. Moreover, the cost of the installation and maintenance of the LUT is high. For example, each LUT must join the COSPAS-SARSAT.
There is another method for transmitting GPS signals, i.e., the wireless communication. For example, GSM or GP RS can be used to transmit data. The primary problem with the wireless communication lies in the installation of a huge number of stations. Service providers build the stations and hence control the quality and cost of the wireless communication. There are inevitably areas that are not covered by the stations such as sea areas more than 10 kilometers from coasts. In these areas, it is impossible to use a cell phone to send an SOS signal for in-time rescue.
The present invention is therefore intended to obviate or at least alleviate the problems encountered in the prior art.